How Do You Use a Hyphen?

The hyphen, along with its cousins the en and em dash, may be the most misunderstood punctuation mark in English. Hyphens are used to join parts of a word or compound phrase, as in ex-wife, full-length mirror, and by-the-book negotiations. As the Chicago Manual of Style puts it, “Far and away the most common spelling questions for writers and editors concern compound terms—whether to spell as two words, hyphenate, or close up as a single word.”

One reason that hyphenation is so complex: it changes over time. A tour through the Google nGram view of many common words reveals their hyphenated predecessors: co-operate became cooperate, to morrow became to-morrow and then tomorrow, and good-bye became goodbye (though both are still acceptable). Some modern terms, like website/web site, have recently settled their usage wars, but email/e-mail is still anyone’s guess. Email may be slowly winning that battle, though uses of e-book outnumber the closed ebook and eBook. A dictionary definition is often the best place to go to seek clarification, or at least understand your options.

Another reason hyphenation can be confounding is that the best practices of usage leave room for interpretation. The main function of hyphens in compound modifiers, or groups of words working together to modify a noun, is to eliminate ambiguity of meaning. For example, in the phrase “up-to-date technology,” we hyphenate “up-to-date” to signal that these three words are to be read as one concept, or adjective, functioning to modify the word “technology.” This way, nobody will make the mistake of reading this phrase as an expression of readiness to go on a romantic date with technology, or as a readiness to mark technology with the day, month and year. In another example, a “heavy-metal detector” detects heavy metals (or perhaps heavy-metal music), but a “heavy metal detector” is a metal detector that is heavy. However, ambiguity can be a subjective matter; as the Chicago Manual states: “Where no ambiguity could result…hyphenation is not needed.”

Age terms are another stumbling point for many. The hyphenation in the following two examples is appropriate: I have to babysit my three-year-old cousin; he has a five-year-old. However, in the following sentence in which the age comes after (rather than before) the noun it modifies, no hyphenation is needed: Sheila is seven years old. One trick of the trade is to look for the plural of “years” in such constructions. If the word “years” is plural, chances are the construction does not need hyphenation.

Compound modifiers in which the adverb ends in -ly do not take a hyphen, as in overly thorough exam. In addition to numerous sections devoted to hyphens, the Chicago Manual also offers a 10-page hyphenation table, which any good copy editor finds indispensable.

What problems do you have with hyphens? Do you have any hyphen questions you’d like to see addressed on the Dictionary.com blog?

43 Comments

Obstructionist: My, oh my folks. What bee got into your bonnet over this one word. Your political slip is showing. The distortion of language is a an age old technique of controlling its use. It is commonly used in politics and has proven to be a valuable propaganda tool by many governments. The interesting fact is, I personally know people on the left, right, and center that are obstructionists. It is not limited to any particular kind of person, whether male, female, or undecided. It is not limited to any particular political body either. It reflects the behavior of an individual. Any race. Any creed. Any sex. To use it as a pejorative in order to make a political point is absolutely obstructionist as it tries to silence dissent. Therefore, your blog site is a bald faced obstructionist site for it impugns only one segment of the political life in America. The segment you chose to disparage. Congratulations on both your obstructionism and prejudice.

Haaaaaa! B-) as on eof today’s rap artists I feel we should be allowed yo use hyphens whenever we please because we as the youth of today speak in “SLANG” and “TWANG” , so it becomes quiete a challenge for us to change the ways in which we use certain symbols ….but moving forward, let us make use of them in te right manner so out following generation will learn from their seniors B-)

Thanks for the little mnemonic device SEGA. Image, “I’ll give you twenty-one hundred dollar bills” versus, “I’ll give you twenty one hundred dollar bills”. A difference of $100 to be sure if one doesn’t use either the hyphen or the dollar sign.

Well, I won’t be reading the manual (start in Chicago and drive north until the arctic ocean and you’ll understand), but I get the point conveyed. It reminds me slightly of a tumblr chat I saw that went something like this:
English is so confusing, since read rhymes with lead and read rhymes with lead but read doesn’t rhyme with lead and read doesn’t rhyme with lead.
MIND BLOWN
Generally, I only use hyphens in numbers, tmeses, and the places that seem right, but not much in words.

I’ve always written “web site” as two words, as it can be rewritten as “a site on the web”. Not the best example, but it leads into something else you see a lot of today: web sites, games, and other on-line applications spelling “log in” and “log out” as single words. I mean, you wouldn’t say “I logoutted of the game.” You’d say “I logged out of the game.”

You say you don’t need to hyphenate an age when it’s after the noun it modifies. But then you say it’s when the word “years” is plural. So suppose your example “Sheila is seven years old” were instead “Sheila is a seven-year-old”? Wouldn’t you need to hyphenate it then? Doesn’t that make your statement about the age being after the noun misleading and wrong?

Great blog post, I really enjoyed reading. But, like Tyler L, (or is it: like – Tyler L -?) I am intrigued about the usage of the em dash.

X states some examples of the em dash as follows:

”
You are the friend—the only friend—who offered to help me.

Never have I met such a lovely person—before you.

I pay the bills—she has all the fun.

A semicolon would be used here in formal writing.
”

If I were to write these sentences myself I would most likely use commas or semi-colons (semicolons?) in their place. I gather that eiter would be grammatically correct? If this is so, how do authors capitalise on the usage of em dashes to add to their writings?

As a graphic designer I am aware that there are three types of “dashes” that are often confused. Indeed, most people are not even aware of these parts of writing.

As mentioned above, the hyphen conjoins two words (or a prefix/suffix and a word) to form a new word. The hyphen is also used between syllables when a word is broken at the end of a text line. The hyphen should never be confused with a dash.

Second is the “n dash”. Longer than a hyphen, the n dash connects two equal but separate words (usually nouns) in the same way as an ampersand (&) to indicate a combined identity. The n dash can also be used as an abbreviation in place of “to”, “through”, and other connecting words, e.g., instead of writing 2pm to 4pm, you might write 2–4pm.

The third dash is called an “m dash” (—) which is the longest (an ‘m’ space as opposed to an ‘n’ space). The m dash is “used to indicate an abrupt change of ideas, but should be used sparingly. It can be used for visual effect in place of commas or parenthesis. The m dash may also be used to indicate a summarizing thought or afterthought at the end of a sentence, or to set off a word or phrase for emphasis.”

You briefly mention the en and em dashes in the beginning of the blog, and I am wondering how their usage differs, if at all, from the hyphen. I enjoy reading and writing stories, and from what I’ve observed, the em dash usually gets used to insert a separate thought into a sentence in the place of parentheses or a semicolon, or to signify that a person speaking has been abruptly cut off before his/her thought could be completed. As least, this is what I think the usage is; I’m not entirely sure, which is why I’m writing to you. Then there is the en dash, the middle of the three, which I am not really sure how to use at all. I know authors have their own styles of writing, which oftentimes break the rules of grammar, but I’m hoping you could tell me more about what those rules actually are. Thank you for your advice!
Sincerely,
Loyal Scarlet

You are correct regarding the em-dash. I think of the en-dash as being used in place of the word “to” in ranges: 1900–1910, 3–5 years old, etc. However, if “from” is used, I prefer “to” over a hyphen, as per Chicago Manual of Style. The en-dash is also used in place of a hyphen when one of the two elements being joined is an open compound: Pre–Civil War era
Pulitzer Prize–winning, etc.